51 [1] Guard your steps when you go to the house of God. To draw near to listen is better than to offer the sacrifice of fools, for they do not know that they are doing evil. 2 [2] Be not rash with your mouth, nor let your heart be hasty to utter a word before God, for God is in heaven and you are on earth. Therefore let your words be few. 3 For a dream comes with much business, and a fool's voice with many words.
4 When you vow a vow to God, do not delay paying it, for he has no pleasure in fools. Pay what you vow. 5 It is better that you should not vow than that you should vow and not pay. 6 Let not your mouth lead you[3] into sin, and do not say before the messenger[4] that it was a mistake. Why should God be angry at your voice and destroy the work of your hands?
Matthew Henry's Commentary on Ecclesiastes 5:1-6
Commentary on Ecclesiastes 5:1-3
(Read Ecclesiastes 5:1-3)
Address thyself to the worship of God, and take time to compose thyself for it. Keep thy thoughts from roving and wandering: keep thy affections from running out toward wrong objects. We should avoid vain repetitions; copious prayers are not here condemned, but those that are unmeaning. How often our wandering thoughts render attendance on Divine ordinances little better than the sacrifice of fools! Many words and hasty ones, used in prayer, show folly in the heart, low thoughts of God, and careless thoughts of our own souls.
Commentary on Ecclesiastes 5:4-8
(Read Ecclesiastes 5:4-8)
When a person made engagements rashly, he suffered his mouth to cause his flesh to sin. The case supposes a man coming to the priest, and pretending that his vow was made rashly, and that it would be wrong to fulfil it. Such mockery of God would bring the Divine displeasure, which might blast what was thus unduly kept. We are to keep down the fear of man. Set God before thee; then, if thou seest the oppression of the poor, thou wilt not find fault with Divine Providence; nor think the worse of the institution of magistracy, when thou seest the ends of it thus perverted; nor of religion, when thou seest it will not secure men from suffering wrong. But though oppressors may be secure, God will reckon for all.